The invention relates generally to dredging, and, more particularly, to a material distribution vessel and a method for distributing material recovered in a dredging operation.
Due largely to erosion, the waterways of many areas of the world are becoming choked with silt and the like. As the waterways become more and more shallow, certain problems arise. For example, navigation through the waterways becomes difficult or altogether impossible. In addition, the risk of flooding adjoining areas of a waterway increases as the depth of the waterway decreases.
Over the years, many dredging techniques have been devised. Perhaps the most popular dredging technique involves a vacuuming dredge which sucks silt and the like from the bottom of the waterway through a conduit or a hose. This technique is disadvantageous in several respects. For example, it collects large volumes of water in the dredging process. As a result, the material recovered by this dredging technique is largely a liquid mixture that is difficult to handle and dispose of. By way of another example, the vacuuming technique mentioned above tends to disturb the bed of the waterway in a manner that mixes silt and impurities imbedded in the silt into the water. Some of these impurities may be toxic (e.g., lead and mercury). Dredging with this old technique can, therefore, pose an environmental hazard. Due to these and other difficulties, dredging a waterway using the vacuuming technique is an expensive, time-consuming and hazardous proposition.
Recently, Caterpillar(copyright) has invented a new dredging assembly. The dredging assembly is a large wheel that rolls along and slices into the bed of a waterway. The wheel is compartmentalized by slicing blades that slice and pick-up segments of the bed of the waterway as the wheel turns in a fashion similar to a cookie cutter slicing cookies from dough. The development of this new dredging technology has made it possible to dredge waterways in a much more efficient, cost-effective manner. Specifically, because the dredging wheel lifts large segments of silt from the waterway bed, the material it recovers is largely solid and undisturbed, is not mixed with much (if any) additional water during dredging, and, thus, can be more efficiently handled than material recovered by the prior art vacuuming system discussed above.
While the development of the Caterpillar(copyright) dredging wheel offers a significant opportunity to recover material from the waterways of the world and to restore those waterways to navigable depths, it has also given rise to a new set of technological problems from the material handling perspective. Specifically, now that it is possible to quickly dredge large volumes of substantially solid material from a waterway, it is necessary to develop apparatus and systems for handling, transporting and/or disposing of the material recovered by the dredge.
In accordance with an aspect of the invention, a method is disclosed for constructing an island in a waterway with material recovered in a dredging operation. The method comprises the step of positioning a material distribution vessel at a first island building area in a waterway. The methods also includes the steps of: supplying a conveyor system of the material distribution vessel with recovered material; depositing the recovered material from the conveyor system into the waterway at a first location in the waterway; moving at least a portion of the conveyor system by at least one of slewing, retracting and extending the at least a portion of the conveyor system; and depositing the recovered material from the conveyor system into the waterway at a second location in the waterway. The first and second locations are located within the first island building area.
In accordance with another aspect of the invention, a material distribution vessel is disclosed for distributing material recovered in a dredging operation. The material distribution vessel comprises a hull; a propulsion system for selectively moving the hull through a waterway; and a conveyor system supported by the hull. The conveyor system has a first end for receiving recovered material and a second end for depositing the recovered material. At least a portion of the conveyor system is movable relative to the hull to move the second end to a desired position. The material distribution vessel also includes at least one support pad. The at least one support pad is movable in at least a vertical direction to support the hull on a bottom of the waterway.